ONVIF trigger support

[andrewgerm]

Would it be possible to add a feature allowing us to trigger recording for a camera, based on an ONVIF service trigger? This would leave motion detection processing on the camera, freeing up server and network resources, and allow us to keep using lower end hardware in a home environment.
MotionEye already works great for viewing / re-streaming / remote viewing / multi-user permissions. Adding the ONVIF would be great to allow an IP camera to then record to an internal SD card, and NVR HDD.
Happy / eager to help test new developments.